Battery life for personal computing devices has become a leading market differentiator among manufacturers' product offerings. Battery-powered performance becomes more important as the size and power of processing circuits continually increases to keep pace with the proliferation of software and operating system requirements. Also, users are becoming ever-more reliant on longer-term and more reliable remote computing sessions.
Accordingly, system designers are continually working to extend the operating life of computing devices, such as notebooks and laptops, when running on battery power. Standards exist for power reduction schemes, such as the Advanced Power Management (APM) system which is published by Microsoft Corporation of Redmond, Wash. and Intel Corporation of Santa Clara, Calif. Computer systems that operate in accordance with the APM standard are responsive to idle calls from an operating system in detecting or predicting inactivity. In response to an idle call, each application program returns an idle indication to the operating system if it is, in fact, idle. The operating system initiates power savings routines if predetermined conditions exist regarding the state of the idle indications.
The APM system defines four power management states: a normal state, a standby state, a suspend state, and an off state. The normal state is substantially the same as a system operating under normal operating conditions that does not perform power reduction routines. The off state is substantially the same as a system that has been powered down and requires a full start up sequence when normal operation is resumed.
The standby state uses less power than the normal state, yet it leaves the complete state of the computer system intact and thus immediately available for continued operation as of the last command. In the suspend state, more drastic power management initiatives are sought for longer periods of inactivity. The goal here is to reach an absolute minimum power consumption while not requiring a full restart sequence when the suspend state is ended.
While various proposed power management methodologies such as the APM system have been found operable, with the continued increase in control circuit complexity, and the continued reliance on long-term battery powered usage, there remains a continued need for improvements in the manner in which power consumption is managed. It is to such improvements that the claimed invention is generally directed.